diff --git a/Commands/Information/CmdInfo.cs b/Commands/Information/CmdInfo.cs
index 087b55f7e..38fe66cb3 100644
--- a/Commands/Information/CmdInfo.cs
+++ b/Commands/Information/CmdInfo.cs
@@ -55,7 +55,7 @@ namespace MCGalaxy.Commands
                 else upTime += up.Seconds + " seconds";
                 Player.SendMessage(p, upTime);
                 if (Server.updateTimer.Interval > 1000) Player.SendMessage(p, "This server is currently in &5Low Lag" + Server.DefaultColor + " mode.");
-            }
+            }            	
         }
         public override void Help(Player p)
         {
diff --git a/Games/ZombieSurvival/ZombieGame.Game.cs b/Games/ZombieSurvival/ZombieGame.Game.cs
index f59d981a8..e898551f3 100644
--- a/Games/ZombieSurvival/ZombieGame.Game.cs
+++ b/Games/ZombieSurvival/ZombieGame.Game.cs
@@ -24,7 +24,8 @@ namespace MCGalaxy.Games {
         
         public override bool HandlesManualChange(Player p, ushort x, ushort y, ushort z,
                                                  byte action, byte tile, byte b) {
-            
+            if (Status == ZombieGameStatus.NotStarted 
+                || (p.level == null || !p.level.name.CaselessEq(CurrentLevelName))) return false;
             if (CurrentLevel.BuildType == BuildType.NoModify) {
                 p.RevertBlock(x, y, z); return true;
             } else if (CurrentLevel.BuildType == BuildType.ModifyOnly 
@@ -65,7 +66,8 @@ namespace MCGalaxy.Games {
         
         public override bool HandlesMovement(Player p, ushort x, ushort y, ushort z,
                                              byte rotX, byte rotY) {
-            if (p.level == null || !p.level.name.CaselessEq(CurrentLevelName)) return false;
+            if (Status == ZombieGameStatus.NotStarted 
+                || (p.level == null || !p.level.name.CaselessEq(CurrentLevelName))) return false;
             if (!p.referee && noRespawn) {
                 if (p.pos[0] >= x + 70 || p.pos[0] <= x - 70 ) {
                     p.SendPos(0xFF, p.pos[0], p.pos[1], p.pos[2], p.rot[0], p.rot[1]);
diff --git a/Levels/BlockQueue.cs b/Levels/BlockQueue.cs
index b978624de..c9c46e5a4 100644
--- a/Levels/BlockQueue.cs
+++ b/Levels/BlockQueue.cs
@@ -24,6 +24,7 @@ namespace MCGalaxy {
         public static int blockupdates = 250;
         static System.Timers.Timer blocktimer = new System.Timers.Timer(100);
         static bool started = false;
+        static BufferedBlockSender bulkSender = new BufferedBlockSender(null);
 
         public static void Start() {
             blocktimer.Elapsed += delegate {
@@ -33,6 +34,7 @@ namespace MCGalaxy {
                     Level[] loaded = LevelInfo.Loaded.Items;
                     foreach (Level l in loaded)
                         ProcessLevelBlocks(l);
+                    bulkSender.level = null;
                 } catch (Exception ex) {
                     Server.ErrorLog(ex);
                     throw;
@@ -56,30 +58,35 @@ namespace MCGalaxy {
             p.level.blockqueue.Add(item);
         }
         
-        static void ProcessLevelBlocks(Level l) {
+        static void ProcessLevelBlocks(Level lvl) {
             try {
-                if (l.blockqueue.Count < 1) return;
+                if (lvl.blockqueue.Count < 1) return;
+                bulkSender.level = lvl;
                 int count = blockupdates;
-                if (l.blockqueue.Count < blockupdates || l.players.Count == 0)
-                    count = l.blockqueue.Count;
+                if (lvl.blockqueue.Count < blockupdates || lvl.players.Count == 0)
+                    count = lvl.blockqueue.Count;
                 Level.BlockPos bP = default(Level.BlockPos);
 
                 for (int c = 0; c < count; c++) {
-                    block item = l.blockqueue[c];
+                    block item = lvl.blockqueue[c];
                     bP.name = item.p.name;
                     ushort x, y, z;
-                    l.IntToPos(item.index, out x, out y, out z);
+                    lvl.IntToPos(item.index, out x, out y, out z);
                     
                     bP.index = item.index;
                     bP.SetData(item.type, item.extType, item.type == 0);
-                    l.Blockchange(item.p, x, y, z, item.type, item.extType);
-                    l.blockCache.Add(bP);
+                    if (lvl.DoBlockchange(item.p, x, y, z, item.type, item.extType)) {
+                        bulkSender.Add(item.index, item.type, item.extType);
+                        bulkSender.CheckIfSend(false);
+                        lvl.blockCache.Add(bP);
+                    }                    
                 }
-                l.blockqueue.RemoveRange(0, count);
+                bulkSender.CheckIfSend(true);
+                lvl.blockqueue.RemoveRange(0, count);
             } catch (Exception e)  {
                 Server.s.ErrorCase("error:" + e);
-                Server.s.Log(String.Format("Block cache failed for map: {0}. {1} lost.", l.name, l.blockqueue.Count));
-                l.blockqueue.Clear();
+                Server.s.Log(String.Format("Block cache failed for map: {0}. {1} lost.", lvl.name, lvl.blockqueue.Count));
+                lvl.blockqueue.Clear();
             }
         }
 
diff --git a/Levels/BufferedBlockSender.cs b/Levels/BufferedBlockSender.cs
index f0885279c..c7f14b3cc 100644
--- a/Levels/BufferedBlockSender.cs
+++ b/Levels/BufferedBlockSender.cs
@@ -24,7 +24,7 @@ namespace MCGalaxy {
         int[] indices = new int[256];
         byte[] types = new byte[256];
         int count = 0;
-        Level level;
+        public Level level;
         
         public BufferedBlockSender(Level level) {
             this.level = level;
diff --git a/Player/Player.cs b/Player/Player.cs
index 92a190f2b..b9ed6ec7a 100644
--- a/Player/Player.cs
+++ b/Player/Player.cs
@@ -951,7 +951,7 @@ Next: continue;
         internal void RemoveInvalidUndos() {
             UndoDrawOpEntry[] items = UndoDrawOps.Items;
             for (int i = 0; i < items.Length; i++) {
-                if (!items[i].IsValid(p))
+                if (!items[i].IsValid(this))
                     UndoDrawOps.Remove(items[i]);
             }
         }
diff --git a/Player/Undo/UndoDrawOpEntry.cs b/Player/Undo/UndoDrawOpEntry.cs
index 7e1e06153..de0082c3f 100644
--- a/Player/Undo/UndoDrawOpEntry.cs
+++ b/Player/Undo/UndoDrawOpEntry.cs
@@ -30,12 +30,14 @@ namespace MCGalaxy.Util {
         
         public void SetStart(Player p) {
             StartNode = p.UndoBuffer.Tail;
-            StartIndex = StartNode.Items.Count;
+            if (StartNode != null)
+                StartIndex = StartNode.Items.Count;
         }
         
         public void SetEnd(Player p) {
             EndNode = p.UndoBuffer.Tail;
-            EndIndex = EndNode.Items.Count;
+            if (EndNode != null)
+                EndIndex = EndNode.Items.Count;
         }
         
         public bool IsValid(Player p) {